Mucous Cysts
Recognising the Symptoms and Signs
Ali Phillips | Hand & Wrist Specialist
What is this bump on my fingertip?
I'm Ali Phillips. Noticing a new lump on your finger, especially near the nail, can be concerning. Often, this is a harmless mucous cyst, which is a sign of underlying arthritis in the joint. This guide will help you understand what it is and what we can do about it.
Book a ConsultationWhat is a Mucous Cyst?
A mucous cyst is a small, non-cancerous, fluid-filled sac that forms on the top of the finger, usually near the base of the fingernail. Think of it as a small blister under the skin. The fluid inside is thick and jelly-like, similar to the natural fluid that lubricates your joints.
These cysts are almost always a sign of "wear-and-tear" arthritis (osteoarthritis) in the fingertip joint (the DIP joint). As the joint wears down, small bone spurs can form, which can cause the joint lining to bulge out, creating the cyst.
What are the symptoms of a Mucous Cyst?
A Visible Lump
A small, round, and sometimes translucent bump on the top of the finger, near the last joint.
Nail Deformity
The pressure from the cyst can cause a groove, ridge, or split to form in the fingernail as it grows.
Pain or Discomfort
While often painless, the cyst can become tender, especially if it gets knocked or becomes inflamed.
Is Your Fingertip Bump Bothering You?
If a lump on your finger is causing pain, affecting your nail, or you're simply worried about it, getting an accurate diagnosis is the first step towards peace of mind. Let's talk about your options.
Get a Clear DiagnosisHow will I diagnose your finger lump?
Diagnosis is usually very straightforward. In most cases, I can diagnose a mucous cyst simply by looking at it and examining your finger. An X-ray is often helpful to check the health of the underlying joint and look for any arthritic bone spurs.
How can I help you get better?
Treatment is only needed if the cyst is painful or causing problems with your nail. Many cysts cause no trouble and can be safely left alone.
Observation Many mucous cysts cause no trouble and can be simply monitored. They often disappear on their own without any treatment.
Aspiration (Draining) This involves draining the fluid from the cyst with a needle. This often provides only temporary relief as the cysts very often refill over time.
Surgery is a very effective option when a cyst is painful, repeatedly gets infected, or is causing a significant nail deformity.
What does the surgery involve?
The procedure is a minor operation performed under local anaesthetic. I make a small incision over the cyst, remove it, and also remove the underlying bony spur (osteophyte) from the joint, which is the root cause of the problem. This significantly reduces the chance of the cyst coming back.
Benefits
- Effectively removes the lump
- Addresses the underlying cause (the bone spur)
- Very low rate of recurrence
- Allows the nail to grow normally again
Small Risks
- Infection (about 1 in 100 cases)
- Stiffness in the fingertip joint
- Scar tenderness
- Permanent nail deformity (rare)
Frequently Asked Questions
No, you can be reassured that mucous cysts are always benign (non-cancerous). However, any new lump should be properly diagnosed by a specialist.
No, you should never try to pop or drain a cyst yourself. The skin over it is very thin, and breaking it can introduce bacteria from your skin directly into your joint, causing a serious infection (septic arthritis).
Draining a cyst (aspiration) only removes the fluid. It doesn't address the underlying cause, which is the connection to the arthritic joint and the bone spur. Because of this, the fluid almost always comes back. Surgical removal of the cyst and the bone spur has a much lower rate of recurrence.
Yes, in most cases. Once the pressure from the cyst is removed from the base of the nail, the nail will grow out normally again over the next few months, and the groove will disappear.
Recovery is usually very quick. You'll have a small dressing on your finger and will need to keep it clean and dry for about two weeks. You can use your hand for light activities almost immediately, and most people are back to normal within a few weeks.
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